<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>Title</title>
    <style>
        #d1{
            width: 200px;
            height: 200px;
            border:10px solid red;
            /*设置圆角：值越大越圆，超过边框的一半则为正圆*/
            border-radius: 200px;
        }
        #d2{
            width: 300px;
            height: 300px;
            border: 1px solid blue;
            /*默认情况下给元素添加内边框距会影响元素的宽高*/
            padding-top: 100px;
            padding-left: 100px;
            /*天骄此样式后内边距将不再影响元素的宽高*/
            box-sizing: border-box;
        }


    </style>
</head>
<body>
<div id="d1">边框测试</div>
<div id="d2">内边距测试</div>
</body>
</html>